Process of making crockery wash-tubs



(No Model.)-

0. 111111111111. PRDCESS OP MAKING CROGKERY WASH TUBS. 110. 436,413.Patented Sept. 16, 1890.

UNITED STATES APATENT OFFICE.

CHARLES GRAHAM, OF BROOKLYN, NEW YORK.

PROCESS OF MAKING CROCKERY WASH-TUBS.

SPECIFICATION forming part of Letters Patent No. 436,413, datedSeptember 16, 1890.

Serial No. 280,463. (No model.)

To @ZZ whom it may concer/1,:

Be it known that I, CHARLES GRAHAM, of Brooklyn, Kings county, in theState of New York, have invented a cert-ain new and useful Improvementin Crockery Wash-Tubs, of which the following is a specication.

It has been found practicable to make rectangular vessels with inclinedfront sides suitable for stationary wash-tubs bysh apin g them, with suitable precautions, in wet clay, drying and burning in kilns in the samemanner as other crockery articles. I do the same. It is desirable thatsuch tubs shall present a clear white interior surface. This has beenheretofore attained by making them entirely of clay which burns white.An objection to such lies in the great fragility before burning while inthe condition known as biscuit.7 It involves great care in the handlingand risk of much loss by breakage.

It has long been known that pottery articles may be made of clay whichwill burn yellow or brown, and lined with a wash of clay which burnswhite. Small articles, as pipkins, have long been made in that manner,the-biscuit being tough and able to endure rougher handling thanall-white ware. An objection to such compound construction of thecrockery lies in the liability of the thin coating to flake off in theburning or at some subsequent period while the article is in use.

I have discovered means for insuring the adhesion of the thin coating ofwhite clay to a body of cheaper and tougher biscuit. By this means I amable to produce wash-tubs having their main bodies of clay, which islower in cost and maintains its integrity more reliably in the handlingwhich is necessary previous to the burning, and which, althoughpresenting unattractive tints, various shades and streaks of dullyellow, red, and brown on the exterior, are white and clear on theirinner faces, the only surfaces where these qualities are important. Iproduce the bottom and four sides of the tub from properly-made slabs ofevenly-Worked tough clay, and by thoroughly kneading the junctionseffect a reliable union. I treat such body by pressure in dies orotherwise to bring it to the exact size and form desired, a littlelarger than the finished tub required, to allow for shrinking. So farthe manipulation is the same as with ordinary Crockery wash-tubs, exceptthat I am indifferent with regard to the color of the main body, butonly anxious to secure a tough biscuit, the shrinkageof which inburningshall be, as nearly as possible, equal to that of the white warewith which its interioris tobelined. The body thus formed is exposed tothe air in the shade until it is nearly, but not quite, dry. Itscondition may be described as leathery. Practice will be required todetermine when this point is reached. It is important that the clay besufficiently dry to have much strength, and yet that it be sufficientlydamp to have its inner surface rapidly softened on the reception of thewet coating` to be applied there. Now, having worked with clear water tothe consistency of cream a liberal quantity of white clay-bywhich I meanthat which will produce white Crockery or analogous white ware when1burned-I apply it rapidly and as uniformly as practicable in a thincoating, covering the entire interior. I have, in my experiments,edected this by distributing the material roughly on the inner surfacesfrom a cup or other vessel, and then immediately spreading it by abrush. The nearly-dried biscuit will absorb the moisture from thiscoating, so that it will dry rapidly, and in a short time--two or threehours, more or less it will be so far dried as to be ready for a secondcoating. This is applied in the same manner. The water from this secondcoat will soften the first coat and also the adjacent portion of themain body. When this softening has reached a certain stage, determinedby practice-say about one or two hours, under the conditions whichobtain in the dry atmosphere in this country in clear weather-I treatthe whole inner surface by rubbing rst with a piece of vulcanized softrubber held at an inclination and drawn over the entire surface severaltimes,moving up and down and horizontally on all the four sides andsimilarly cross wiping or rubbing the bottom. A strong pressure isapplied on this rubber during the early stages of the treatment; but thepressure is gradually lesscned as it proceeds, until it is finished withvery light wiping. A little later in the drying operation the wholesurface is slicked with a large knife. The pressure applied during thistreatment also should be firm at IOO the commencement and grow less asthe work proceeds. The biscuit thus lined, with the lining compressedupon and into intimate union with the main body, is now allowed to dryfurther, and is subsequently glazed and burned, care being taken to keepthe smoke of the kiln from the interior in the same manner as with allwhite Ware. I believe that the rubbing has an eect analogous to thekneading by which potters have long joined separately-formed parts ofCrockery- Ware, and by which the live separate flat slabs employed inbuilding up the body of this kind of tubs arel joined.

I am not aware that a lining has before been compressed upon a body bysuch treatment or by any analogous treatment. My experiments indicatethat the lining produced by two coats of the creamy-white clay appliedin this manner and compressed on the body with patient manipulation issufciently thick to produce substantially the same eect on the eye asclear white ware, and is reliably joined, so that it Will endure all theordinary and extraordinary treatment to which the tub is subjected instorage, transportation, and use.

The accompanying drawings form apart of this specification.

Figure 1 is a cross section of the completed tub. The remaining figuresare on a larger scale. Fig. 2 is a cross-section showing a portion ofthe tub before the lining is applied. Fig. 3 is a cross-section showinga portion of the tub after the lining is applied and before the rubbing.Fig. 4 is a corresponding sec-tion showing the condition attained afterthe rubbing has eiected the re quired intimate union.

In all the figures, A is the main body, B the White-ware lining, and cthe junction. Before the rubbing the junction c is smooth andincomplete. After the rubbing it is irregular, the particles of the onebeing impressed into and partially interwoven with the particles of theother material.

Modiications may be made in the details Without departing from theprinciple or sacrificing the advantages of the invention. I can smoothwith the rubber the Whole interior of the body before applying the firstcoat, and again after applying the first coatbefore applying the second.My experiments indicate that there are some advantages in doing this;but I do notesteem such rubbings previous to the rubbing on the finalcoat essential to success.

I claim as my invention- The method described of uniting a lining ofwhite-burning clay with a body of tougher clay by first shaping andpartly drying the body A of tough clay and preparing the White- -burningclay in a semi-Huid or creamy condition, then applying the semi-fluidclay as a Wash to the inside of the vessel'in one or more coats,yallowing it to stand a sufficient time to allow the moisture to becomenearly or quite equalized throughout the whole interior portion of thevessel, and then agitating the particles and blending them by rubbing,as herein specified.

In testimony .whereof I have hereunto set my hand, at New York city,this 19th day of July, 1888, in the presence of two subscribingwitnesses.

CHAS. GRAHAM. Writnesses:

THOMAS DREW STETsoN, H. A. J oHNsToNE.

